Power Cord Order of importance

Currently,  I have Kimber Power Cords for the Amps and Pre-amp.  They are ok.  I have an Inakustic 2404 Power cord for my DAC.  I am buying a music server soon.  I am thinking about upgrading Power cords in two components.  Which components should get the reference level PC's?  I am probably going to spend around $3k for two new PC's.  

Mono Amps
Pre- Amp
DAC
Server

I am looking for the biggest impact on sound quality from a component perspective.